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Sandblasting Creosote out of the Firebox?

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by Eric Johnson, Feb 29, 2008.

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  1. Eric Johnson

    Eric Johnson Mod Emeritus

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    I've never used a sandblaster, but I know they can be rented, and I have a number of projects coming up this summer that would benefit from a good sandblasting. Actually, I'd be the biggest beneficiary. It occurred to me that if leaving creosote in the firebox over the summer is a potential corrosion problem, would there be anything to be gained from sandblasting it all off of there and then maybe putting a layer of oil on the steel?

    More trouble than it's worth?
    Bad for the boiler?
    Risk that I might get into it too much and wind up buying a compressor and accessories?

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  2. eekster

    eekster New Member

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    Eric, if you sandblast the inside of the firebox, the inside is powdered coated wich helps protect the steel, so I would say no. When I first started burning mine last year I used a putty knife to try to clean it while it was still warm and scraped off the coating exposing the bare steel. I now wait till the boiler is cool and use a putty knife to clean it at the end of the season. That's what Zennon's daughter told me to do.
    Keith
  3. Sting

    Sting Feeling the Heat

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    May I suggest you brush the HX and exposed surfaces as best as possible
    Yes dirty job - call that TV host guy ... but suit up - duct tape your sleeves and wade in.
    Then find some LPS 3 in aerosol if you don't mind the propellant - or in gallon bulk container and and liberally apply with a pump sprayer. It will creep to many surfaces you cannot see and provides wonderful off season protection. Burns off gracefully next season also taking some of that corruption with it for better transfer deficiency.
  4. jebatty

    jebatty Minister of Fire

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    Eric, how much creosote do you get? I'm nearing the end of my first Tarm season, and while there is creosote in the firebox, it is not leaking down to the ceramic firebox base, and it seems to largely burn off with a base of creosote left, in other words, these does not seem to be a continuing build-up.

    How corrosive is creosote? It seems to be a pretty good sealant, having been fixed to the firebox by a lot of heat. Is it actually a benefit?

    Would it be better just to seal up the firebox good to keep moisture out? remove the stove pipe and plug the smoke outlet, plug the forced draft inlets, etc.?
  5. Eric Johnson

    Eric Johnson Mod Emeritus

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    I don't get much. It's just that I've read that it's corrosive, and thought getting it off of there might be a good idea. I think the main problem is condensation mixing with the creosote to form corrosive acids. Currently, if it starts to hang down from the walls and top of the firebox, I scrape it off with the cleaning tools and burn it up.
  6. slowzuki

    slowzuki Feeling the Heat

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    If you can keep the water in it a touch warmer than your air temp you shouldn't have any problems with condensation.
  7. jebatty

    jebatty Minister of Fire

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    Creosote is regarded as being poisonous. Are there precautions to be taken in cleaning/removal of creosote?

    A wooed construction journal states that creosote is soluble in alcohol and benzene -- I would not recommend benzene, as it is a major component of gasoline and is extremely flammable.

    The following article suggest that all of the following have good resistance to creosote corrosion:
    carbon steel; cast iron; 302, 304, 316 and 416 stainless steel.

    http://www.engineeringtoolbox.com/metal-corrosion-resistance-d_491.html
  8. rsnider

    rsnider New Member

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    i would think it would be good to clean it as well. sandblasting would work with low pressure on the machine. too much and you could be putting little dents all over the inside of the chamber prob not good. it would be dusty mess of a job for sure sandblasting in such a small area with your head somewhat close the opening of the furnace to see what your doing.

    i was thinking of coating the inside of a new eko with fire brick and the parts not able to place brick refractory cement (furnace cement) so the creosote will never touch the steel. or thinking maybe the creosote will not form as much since it may be a little hotter than the steel alone. someone on here has already tried this hogstroker i think but he did not use cement just the creosote was holding the bricks like a glue. what do you think of the brick and cement idea?
  9. slowzuki

    slowzuki Feeling the Heat

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    The whole point of the cold chamber in the eko is so the wood doesn't gasify too quickly. If you line it with brick it will burn too fast and produce too much wood gas for how much air is used.
  10. rsnider

    rsnider New Member

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    so the first chamber supposed to be so dirty with creosote? would you be able to burn wetter wood if it was to have the bricks in it? if no bricks would it be a good idea to just coat the whole inside with the furnace cement to have some kind of protection from the creosote? just wondering
  11. jebatty

    jebatty Minister of Fire

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    The Tarm manual talks about creosote in the firebox, and the main statement about cleaning creosote is if it drips/runs down onto the ceramic base in the firebox. The manual says that happens rarely, but it must be removed (no instructions as to how). The manual also says the interior of the firebox should be scraped/wire brushed to remove creosote before the boiler is shut down for the season. It appears that creosote in the firebox during the normal period of operation is of no concern.

    As to shutdown, the manual stresses the importance of sealing up the flue outlet, closing the doors, and checking from time to time to make sure there is no condensation in the boiler. The manual also mentions that if after everything is sealed up condensation still forms, then a small light bulb (40w) should be hung in the firebox to evaporate all moisture.

    "It is an inescapable fact that iron in the presence of oxygen and water is thermodynamically unstable with respect to its oxides. Because atmospheric corrosion is an electrolytic process, the presence of an electrolyte is required. This should not be taken to mean that the steel surface must be awash in water; a very thin adsorbed film of water is all that is required. . . . The portion of time spent covered with the thin water film depends quite strongly on relative humidity at the exposure site."
    http://www.key-to-steel.com/Articles/Art60.htm

    Thus, it seems that keeping the interior of the boiler dry during the off season is extremely important. The creosote already is an acid, and with the presence of water (humidity), corrosion will follow (corrosion - rust - will occur even without the creosote in the presence of water/humidity). If the interior is kept dry, it appears that there should be minimal to no corrosion, depending on how dry is dry.

    I suspect that for most of us removal of all creosote is an impossibility, but we can keep the interior of our boilers dry.
  12. drizler

    drizler Minister of Fire

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    Have you ever used a sand blaster? I have a couple small ones that run off a medium air compressor more of less. Its a nice for some things but to lean inside something and blast away is going to be hard to see. Not that you really have to I suppose. For a job that size its not worth renting a big monster with a tag along compressor. Its fast alright but overkill I think. A simple siphon in the pail type should do you fine with a 6-10 hp (preferably on the higher side) home unit and 60-80 gallon tank. A smaller one would work but be slower but suffice if its what you already have. If you do blast it use Black Beauty (NAPA) or similar as the silica doesn't cut as well and you need all the help you can get with a home rig. On the other hand blasting is gonna take it right to the raw metal and pit it some to boot. You will need to protect it immediately as it will start rusting that fast in any weather. Might just persuade you to simply scrape it now right? Also you need a decent protective mask and goggles or cheap gas mask or something to keep the dust out of your eyes and lungs. If you do decide to blast leave the garden hose ready to have someone hose you down cause if you go into the house towards the shower your wife will kill you dead. I just jumped into the swimming pool clothes and all. Change your mind yet????????????? I won't bother with the water plugging issues from condensation bla bla bla..........

    If it was me I would attack it with a mask and a cheap 4.5" grinder sporting a stainless cup brush. Makita is best but Forney is about half the price nearly as good and you can get them at true value. A cup brush should do the trick easily enough and possibly a round stainless. I bet its as fast as a smallblaster really and 1/10th as nasty. The cheap Chinese jobs from the flea market really do work almost as well as the name brands, I have 4 of em last count. At least with those you could dust off and tip toe to the shower without being killed, Pick yer poison
  13. Nofossil

    Nofossil Moderator Emeritus

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    I absolutely would not worry about creosote inside the firebox. Moisture is the enemy. My sense is that if you cleaned off a patch of steel, it would rust more than the steel that's sealed under a layer of baked-on creosote.

    The back side of the lower chamber might be more of a concern. Dry ashes that could hold condensation. You're outside where it will see temperature swings.

    I might think about getting a sock full of the water absorbing silica gel beads and sticking it inside for the summer. You can recharge them by baking at low temp, I think.
  14. jebatty

    jebatty Minister of Fire

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    Nofo -- good point -- get ALL ashes out of everything you can, firebox, ceramic tunnel, hx tubes, everywhere. Don't leave any ashes any place to hold moisture. The silica gel also a good idea.
  15. rsnider

    rsnider New Member

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    how about damp-rid sold at lowes. this works great to get moisture out of the air in bathrooms and closets. one in the upper chamber and lower chamber after the good cleaning.
  16. trehugr

    trehugr New Member

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    Eric, you definitely want to reconsider sandblasting...anything. I have extensive experience. Its not something I think your going to enjoy. Even if you do set yourself up with a compressor that can keep up, you will still need to install 1 or more water traps. Sandblasting in it self is an unhealthy process, I cant even imagine adding creosote into the mix. IMOH dont waste your time and money and more importantly, your health.
  17. Eric Johnson

    Eric Johnson Mod Emeritus

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    That's all I need to know, fellas. Thanks.
  18. drizler

    drizler Minister of Fire

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    And last but not least it is the filth of it. I have not ever been dirtier in my life than blasting under a car which a whole lot cleaner than what you are thinkin. I never got that nasty in 5 years of National guard and 4 years active army. Even with a tight hat on you get that grit in your hair and it won't come out for days unless its in your pillow. Not so bad out in the clear air but inside or under something yucch. and that was wearing a Russian Civillian gas mask with the complete rubber cap even. It gets every where. Then the wind starts blowing it around.
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